Animal manure is a valuable fertilizer for crop production, but effective utilization requires knowledge of the manure’s nutrient content. This warrants that the manure be sampled and tested to make informed management decisions. However, there has been low adoption of annual manure testing (ca. 20% of farms). Presumably, this is because farmers view the costs and efforts of testing to be greater than the benefits. To evaluate the monetary value of manure testing, a model was developed. Using published literature values of manure nutrient concentrations and other agronomic factors as inputs, this model assesses how production expenses and incomes change with knowledge of manure’s nutrient content. The model suggests that when applying manure at a nitrogen-limited rate, sampling manure before application increases profits by $20 to $68 ha^-1, and sampling during application increases profits by $3 to $50 ha^-1. When applying manure at a phosphorus-limited rate, profits increase by $4 to $22 ha^-1 when samples are analyzed either before or during application. These results illustrate that manure testing is economically beneficial and indicate that when application is nitrogen limited, manure should be sampled prior to application. If applying manure at a phosphorus-limited rate, sampling during application is recommended.